Electric arc welding is well known, and is performed with a variety of processes using a variety of types of equipment. One electric arc welding process is a pulse spray process, which is typically performed using a wire feeder and a power supply. An example of a prior art power supply used in pulse spray welding is a Miller S64M™ wire feeder. The Miller S64M™ wire feeder may be used with a Miller XMT304™ power supply.
Typically, a pulse spray welding power supply includes a wire feeder, a power source, and a controller, which may be disposed in the same or separate housings. Power is provided from the power source to the wire feeder, and the wire feeder provides the wire and power to the arc. The wire feeder typically includes a controller, which may be part of or separate from the wire feeder, and which controls the wire feed speed based on at least one user-selected input. Additionally, the controller provides a command signal to the power supply which causes the power supply to output a current and voltage at a desired magnitude. The command is produced in response to a user-selected wire feed speed. The power supply provides a specified current by adjusting the output voltage until the desired current is obtained. The current amplitude is often controlled as a function of time, switching between a background current and a peak current, thus creating a pulsed output.
Many prior art systems start a welding process by providing a run-in time, during which wire is fed to the arc at a run-in speed. This allows the wire to move to the work piece. Then, after the run-in ends, the wire is fed at the user selected rate. The run-in may be terminated when the wire reaches the workpiece, or when the arc starts. However, at times the user touches the wire to the workpiece before starting the welding process (by pulling the trigger on the torch). This can cause difficult starts.
Accordingly, it is desirable that a welding power supply and wire feeder include a controller that helps start the weld properly, particularly when the wire is touching the workpiece.